Re: [RFC] Request API and V4L2 capabilities

Nicolas Dufresne
2018-08-23T21:08:13Z

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Le jeudi 23 août 2018 à 16:31 +0200, Hans Verkuil a écrit :
> > I propose adding these capabilities:
> >
> > #define V4L2_BUF_CAP_HAS_REQUESTS 0x00000001
> > #define V4L2_BUF_CAP_REQUIRES_REQUESTS 0x00000002
> > #define V4L2_BUF_CAP_HAS_MMAP 0x00000100
> > #define V4L2_BUF_CAP_HAS_USERPTR 0x00000200
> > #define V4L2_BUF_CAP_HAS_DMABUF 0x00000400
>
> I substituted SUPPORTS for HAS and dropped the REQUIRES_REQUESTS capability.
> As Tomasz mentioned, technically (at least for stateless codecs) you could
> handle just one frame at a time without using requests. It's very inefficient,
> but it would work.

I thought the request was providing a data structure to refer back to
the frames, so each codec don't have to implement one. Do you mean that
the framework will implicitly request requests in that mode ? or simply
that there is no such helper ?

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